1. Field of the Invention
The present invention relates to a tiltable steering device and, more particularly, to an improvement in a structure for pivotably supporting the steering column of a steering device of a vehicle, for the purpose of attaining a compact construction of a tilt adjusting portion of the structure.
2. Related Background Art
A device called tiltable steering device has been known which enables adjustment of height of the steering wheel in accordance with the size of the body of the driver or the position of the driver.
An example of such a tiltable steering device is disclosed in, for example, Japanese Utility Model Application Laid-Open No. 60-144569.
This known tiltable steering device is of a type which is generally referred to as neck swinging type. In this known tiltable steering device, as shown in FIG. 4, a steering column 2 through which a steering shaft extends is divided into two parts: namely, a lower steering column section 3 and an upper steering column section 4, wherein both column sections are coupled to each other by means of a support bracket 5 on the body. The upper steering column section 4 is supported for pivoting motion about an axis provided by horizontal shafts 6, 6 which are provided on both sides of the support bracket 5 as shown in FIGS. 5 to 7.
A connecting mechanism, which is engageable and disengageable by the operation of a tilt lever 7 pivotable about the axis of the horizontal shafts 6, 6, is provided between the support bracket 5 and the upper steering column section 4, the connecting mechanism being switchable between two states: namely, a state in which it connects the upper steering column section 4 and the support bracket 5, i.e., the upper steering column section is fixed against pivoting motion, and a state in which it allows the upper steering column section 4 to move relative to the support bracket 5, i.e., the upper steering column section 4 is allowed to pivot.
Thus, in this tiltable steering device, the upper steering column section 4 is pivotably connected at its one end to the support bracket 5 by means of the horizontal shafts 6, 6 provided on the support bracket 5 which is fixed to the body, e.g., at the underside of the dash board 8. In addition, a first engaging member 9 is fixed to the underside of the upper steering column section 4. The lower surface of the first engaging member 9 is projected along an arc centered at the axis of the horizontal shafts 6, 6. First engaging teeth 10 are provided on the projected underside of the first engaging member 9.
Another horizontal shaft 11 provided on the support bracket 5 pivotably supports one end (left end as viewed in FIGS. 5 and 7) of the second engaging member 12 which is selectively engageable with the first engaging member 9. Second engaging teeth 13 for engagement with the first engaging teeth 10 on the underside of the first engaging portion 9 are formed on the upper end edge (right upper end edge as viewed in FIG. 5) of the second engaging member 12. A shaft 14 connects both lower ends of the tilt lever 7 which is pivotably supported by the horizontal shafts 6, 6 at midst of two leg portions thereof. The shaft 14 carries a roller 15 the upper end of which is held in contact with the underside of the second engaging member 12.
A pin 18 projecting from one lateral side of the second engaging member 12 engages with an inclined slot 17 which is formed in a plate 16 fixed to the tilt lever 7.
According to this arrangement, as the tilt lever pivots counter-clockwise as viewed in FIG. 5, the roller 5 is retracted from the other end (right end as viewed in FIG. 5) of the second engaging member 12 and, at the same time, the other end of the second engaging member 12 is moved downward due to engagement between the inclined slot 17 and the pin 18.
Consequently, the second engaging teeth 13 provided on the upper face of the other end of the second engaging member 12 are disengaged from the first engaging teeth 10 provided on the underside of the first engaging member 9 fixed to the underside of the upper steering column section 4, so that the upper steering column section 4 is allowed to pivot about the axis of the horizontal shafts 6, 6 within a range corresponding to the range of movement of the pin 19 limited by the length of the arcuate slot 20 formed in the support bracket 20, thus enabling an adjustment of the height of a steering wheel fixed to the end of the steering shaft 1 which extends through the upper steering column section 4.
After the adjustment of height of the steering wheel, the driver swings the tilt lever 7 clockwise as viewed in FIG. 5 so that the roller 15 is moved into the underside of the other end of the second engaging member 12 so as to lift the other end of the second engaging member 12 upward, whereby the second engaging teeth 13 formed on the upper edge of the other end of the second engaging member 12 are brought into engagement with the first engaging teeth 10 fixed to the underside of the upper steering column 4, whereby the upper steering column section 4 is fixed against rotation about the axis of the horizontal shafts 6, 6.
The steering wheel is therefore held at the adjusted height. When the steering wheel has been set as described, the tensile spring 21 applies an elastic tensile force to the tilt lever 7, tending the tilt lever 7 to pivot clockwise as viewed in FIG. 5, whereby the roller 15 prevented from unintentionally retracting from the space under the second engaging member 12.
In the described tiltable steering device, the first engaging member 9 is fixed to the underside of the upper steering column section 4, while the second engaging member 12 is pivotably connected to the support bracket 5. This arrangement, however, may be altered such that the first engaging member 9 is fixed to the underside of the support bracket 5, while the second engaging member 12 is pivotably connected to the upper steering column section 4, as shown in FIG. 8.
In the known tiltable steering device constructed and used in the manner described, the connecting mechanism inevitably projects in a large amount from the underside of the steering column 2, because of the presence of the roller 15 under the second engaging member 12. Consequently, problems are encountered such as degradation of the appearance or interference with the driver's knee.